Saturday, December 8, 2012

Shots from 2012 v2 : in mountains

Some other shots from flying Pyrénées mountains this year.

Saturday, November 24, 2012

Shots from 2012

A video made from various flights along past season...

Monday, October 22, 2012

Flying with tufts

On a blue thermal day, I spent some time adding whool tufts at wing/fuselage junction of my LS6. Here is the result :

The objective was to visualize flow separation in the root of LS6 glider.

Result : flow in wing fuselage junction is sensitive to aoa & aileron:flap deflection.
It can be observed in stall :
Separation occurs at lower fuselage attitude when flap increase. Tip : visualize this by looking at tail position vs horizon when separation appears.
It can be observed in normal flight :
In straight flight, separation is not visible. Very slight tuft activity on the fuselage sides.
While circling, separation occurs quite often, particularly on the wing inside turn. This is likely driven by the additionnal aerodynamic load brought by aileron offset ut of the turn to keep bank angle.

Next time :
Tufts should be applied on both sides It could be interesting to pull some G's to see what happens

Sunday, April 22, 2012

Water & McCready setting

In the waiting of proper weather, here is a table that was derived while studying McCready ring value of various sailplane, with various wing loading. It gives you an equivalent additional Mc Cready setting to be representative of polar change due to waterballast.

This is the result of numerical investigation filtered by the "TAR"* method. For sure your marvelous onboard computer knows better...

The objective is to provide simple figures, easy to memorize, per family of glider (Club class/15m/18m/20m/unlimited), to be used with "Standart Mc Cready ring" (like the good old time).

Example : today I fill my LS6 with 80L of water. I should consider increasing by 0.4m/s my McCready setting due this additional wing loading - on top of other setting (80/100*0.5m/s=0.4m/s)

Don't hesitate to use this "enhanced rule of thumb" !

(& keep in mind it is always more efficient to have a McCready setting "a bit too less" than "a bit too much"...)

* "TAR"="That's About Right" method - i.e. there is a certain dose of approximation in all this.

Sunday, April 8, 2012

Still in the workshop

This year I am not exactly as early as wished at finishing yearly work on the LS6, already some good day were missed... Now my Pruefer is coming next week, everything should be fine !

 I am getting trained at using my Drift HD camera, interesting fish eye effect in the garage, which seems even more molded around the glider ;-)

Sunday, April 1, 2012

French oldies

Not exactly sailplane stuff, nevertheless a few interesting views of french prototypes from the 50's, that I numerized from a VHS owned by Jean-Claude Fayer some years ago.

Rare images for some of them.

Monday, January 30, 2012

Back in 2008, I had the opportunity to organize a cession at ISAE wind tunnel, in frame of a student project. It was concern with the characterisation of a sailplane model, the Jibe 2 from Flybiwo.

If found I had stored some image from this cessions, here they are assembled in a short video.

Pure geek material ;-)